(function($) {

  $.extend({
    createUploadIframe: function(id, uri) {
      //create frame
      var frameId = 'jUploadFrame' + id;

      if (window.ActiveXObject) {
        var io = document.createElement('<iframe id="' + frameId + '" name="' + frameId + '" />');
        if (typeof uri == 'boolean') {
          io.src = 'javascript:false';
        }
        else if (typeof uri == 'string') {
          io.src = uri;
        }
      }
      else {
        var io = document.createElement('iframe');
        io.id = frameId;
        io.name = frameId;
      }
      io.style.position = 'absolute';
      io.style.top = '-1000px';
      io.style.left = '-1000px';

      document.body.appendChild(io);

      return io
    },
    createUploadForm: function(id, s) {
      var fileElementId = s.fileElementId;
      //create form	
      var formId = 'jUploadForm' + id;
      var fileId = 'jUploadFile' + id;
      var form = $('<form  action="" method="POST" name="' + formId + '" id="' + formId + '" enctype="multipart/form-data"></form>');
      var oldElement = $('#' + fileElementId);
      var newElement = $(oldElement).clone();
      s.newFileUpload = newElement[0];
      $(oldElement).attr('id', fileId);
      $(oldElement).before(newElement);
      $(oldElement).appendTo(form);
      //set attributes
      $(form).css('position', 'absolute');
      $(form).css('top', '-1200px');
      $(form).css('left', '-1200px');
      for (var h in s.hiddens) {
        if (!s.hiddens.hasOwnProperty(h)) continue;
        var hdn = $("<input type='hidden' name='" + h + "' value='" + s.hiddens[h] + "' />");
        hdn.appendTo(form);
      }
      $(form).appendTo('body');
      return form;
    },

    ajaxFileUpload: function(s) {
      // TODO introduce global settings, allowing the client to modify them for all requests, not only timeout		
      s = jQuery.extend({}, jQuery.ajaxSettings, s);
      var id = new Date().getTime()
      var form = jQuery.createUploadForm(id, s);
      var io = jQuery.createUploadIframe(id, s.secureuri);
      var frameId = 'jUploadFrame' + id;
      var formId = 'jUploadForm' + id;
      // Watch for a new set of requests
      if (s.global && !jQuery.active++) {
        jQuery.event.trigger("ajaxStart");
      }
      var requestDone = false;
      // Create the request object
      var xml = {}
      if (s.global)
        jQuery.event.trigger("ajaxSend", [xml, s]);
      // Wait for a response to come back
      var uploadCallback = function(isTimeout) {
        var io = document.getElementById(frameId);
        try {
          if (io.contentWindow) {
            xml.responseText = io.contentWindow.document.body ? io.contentWindow.document.body.innerHTML : null;
            xml.responseXML = io.contentWindow.document.XMLDocument ? io.contentWindow.document.XMLDocument : io.contentWindow.document;

          } else if (io.contentDocument) {
            xml.responseText = io.contentDocument.document.body ? io.contentDocument.document.body.innerHTML : null;
            xml.responseXML = io.contentDocument.document.XMLDocument ? io.contentDocument.document.XMLDocument : io.contentDocument.document;
          }
        } catch (e) {
          jQuery.handleError(s, xml, null, e);
        }
        if (xml || isTimeout == "timeout") {
          requestDone = true;
          var status;
          try {
            status = isTimeout != "timeout" ? "success" : "error";
            // Make sure that the request was successful or notmodified
            if (status != "error") {
              // process the data (runs the xml through httpData regardless of callback)
              var data = jQuery.uploadHttpData(xml, s.dataType);
              // If a local callback was specified, fire it and pass it the data
              if (s.success)
                s.success(data, status);

              // Fire the global callback
              if (s.global)
                jQuery.event.trigger("ajaxSuccess", [xml, s]);
            } else {
              if (s.error) s.error(xml, status);
              else jQuery.handleError(xml, status);
            }
          } catch (e) {
            status = "error";
            if (s.error) s.error(xml, status, e);
            else jQuery.handleError(s, xml, status, e);
          }

          // The request was completed
          if (s.global)
            jQuery.event.trigger("ajaxComplete", [xml, s]);

          // Handle the global AJAX counter
          if (s.global && ! --jQuery.active)
            jQuery.event.trigger("ajaxStop");

          // Process result
          if (s.complete)
            s.complete(xml, status);

          jQuery(io).unbind()

          setTimeout(function() {
            try {
              $(io).remove();
              $(form).remove();

            } catch (e) {
              jQuery.handleError(s, xml, null, e);
            }

          }, 100)

          xml = null

        }
      }
      // Timeout checker
      if (s.timeout > 0) {
        setTimeout(function() {
          // Check to see if the request is still happening
          if (!requestDone) uploadCallback("timeout");
        }, s.timeout);
      }
      try {
        // var io = $('#' + frameId);
        var form = $('#' + formId);
        $(form).attr('action', s.url);
        $(form).attr('method', 'POST');
        $(form).attr('target', frameId);
        if (form.encoding) {
          form.encoding = 'multipart/form-data';
        }
        else {
          form.enctype = 'multipart/form-data';
        }
        $(form).submit();

      } catch (e) {
        jQuery.handleError(s, xml, null, e);
      }
      if (window.attachEvent) {
        document.getElementById(frameId).attachEvent('onload', uploadCallback);
      }
      else {
        document.getElementById(frameId).addEventListener('load', uploadCallback, false);
      }
      return { abort: function() { } };

    },

    uploadHttpData: function(r, type) {
      var data = !type;
      data = type == "xml" || data ? r.responseXML : r.responseText;
      // If the type is "script", eval it in global context
      if (type == "script")
        jQuery.globalEval(data);
      // Get the JavaScript object, if JSON is used.
      if (type == "json")
        eval("data = " + data);
      // evaluate scripts within html
      //if (type == "html")
      //  jQuery("<div>").html(data);
      //alert($('param', data).each(function(){alert($(this).attr('value'));}));
      return data;
    }
  });
})(jQuery);

